Is Fg the Only Force to Consider for Ft4 in a Pulley System?

[N_L_]

I have some questions about the following problem:

I know that Ft1 and Ft2 are equal. Is Fg the only force that needs to be taken into account for Ft4? Does the force being applied to lift the piano need to be taken into account for Ft3? If not, is it just m*g?

http://img96.imageshack.us/img96/8798/782tm.jpg

 

[Chi Meson]

Assuming that the pulleys are frictionless, the tension is the same throughout the rope (frictionless pulleys can be found only in textbook problems).

Also assuming that the piano is moving at a constant speed, F_T4 is equal to the weight of the piano. More force here is necessary to accelerate the piano upward.

Look at the top pully: how many strands are pulling it down? How much tension in each strand? ("strand" = "rope segment")